Telematics system and method having combined cellular and satellite functionality

ABSTRACT

A vehicle Telematics unit includes a cellular transceiver and a satellite receiver. At least one controller controls the transceiver and the receiver and determines which one to use to communicate with a source of Telematics service. If the transceiver is to be used, the controller receives messages in cellular communications from the source with a cellular network. If the receiver is to be used, the controller receives messages in satellite communications from the source with a satellite network. The controller can programmably control power from a battery to the transceiver and receiver when the vehicle is turned off using discontinuous reception parameters, designated on/off times, a controlled duration, and programmable timers. The transceiver is used to return acknowledgments of messages received. If a message is received with the receiver, the acknowledgment is stored so it can be sent at another time when the transceiver is to be used.

FIELD OF THE DISCLOSURE

The subject matter of the present disclosure generally relates to asystem and method for providing Telematics services for a vehicle usingboth cellular and satellite functionalities.

BACKGROUND OF THE DISCLOSURE

Telematics systems are known in the art that offer Telematics servicesfor vehicles. Typically, the vehicle has a Telematics unit wife anintegrated cellular transceiver. In the U.S., the cellular transceivermay be a CDMA/AMPS transceiver, while a GSM transceiver may be used inEurope. Telematics systems can also use other cellular standards (e.g.,WCDMA). The Telematics systems can provide wireless communication andcan provide remote Telematics services, such as unlocking the doors ofthe vehicle, flashing the headlights of the vehicle, or performing otherautomated actions. These types of remote Telematics services can beespecially useful for a person who has accidentally locked her keys inher car or who is stranded in some remote location.

Existing Telematics units in the vehicle may drain power from thebattery while the vehicle's ignition is off. In addition, becauseexisting Telematics system rely on cellular network coverage to operate,the Telematics system may be unable to perform Telematics services whena Telematics units in a vehicle travels to an area where cellularcoverage is limited or not existent. When the vehicle is out of cellularcoverage, a driver in a remote area without cellular must use a landlinephone or some other means to contact a Telematics service provider torequest service.

The subject matter of the present disclosure is directed to overcoming,or at least reducing the effects of, one or more of the problems setforth above.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments and other aspects of subject matter of the presentdisclosure will be best understood with reference to a detaileddescription of specific embodiments, which follows, when read inconjunction with the accompanying drawings, in which:

FIG. 1 schematically illustrates an embodiment of a Telematics systemhaving a service provider and a Telematics unit according to certainteachings of the present disclosure.

FIG. 2 illustrate a process of operating the Telematics system.

FIG. 3 illustrates a process of checking a battery coupled to theTelematics unit.

FIG. 4 illustrates a process of operating the network access device ofthe Telematics unit to conserver power.

FIG. 5 illustrates a process of operating the satellite receiver of theTelematics unit to conserver power.

FIGS. 6A through 6C illustrate power mode schemes for operating asatellite receiver of the Telematics unit.

While the subject matter of the present disclosure is susceptible tovarious modifications and alternative forms, specific embodimentsthereof have been shown by way of example in the drawings and are hereindescribed in detail. The figures and written description are notintended to limit the scope of the inventive concepts in any manner.Rather, the figures and written description are provided to illustratethe inventive concepts to a person skilled in the art by reference toparticular embodiments, as required by 35 U.S.C. §112.

DETAILED DESCRIPTION

A Telematics system and method are disclosed. In one embodiment, avehicle Telematics unit of a Telematics system includes a cellulartransceiver, a satellite receiver, and at least one controller. Thecellular transceiver is used for communicating cellular communicationswith a source of Telematics service via a cellular network. Thesatellite receiver is used for receiving satellite communications fromthe source via a satellite network. The at least one controller iscommunicatively coupled to the cellular transceiver and the satellitereceiver and establishes communication with the source using either oneor both of the cellular transceiver and the satellite receiver.

During operation, the controller determines whether to use the cellulartransceiver or the satellite receiver to communicate with the source. Todetermine whether to use the cellular transceiver or the satellitereceiver, the controller determines whether the cellular transceiver iscapable of communicating with the cellular network, whether the cellulartransceiver is out of communication range of the cellular network,whether the cellular network is congested, whether an expense for usingthe cellular network exceeds a predetermined amount, and/or whetherusing the cellular network is not preferred.

If the controller determines that the cellular transceiver is to beused, the controller operates in a cellular mode to receive messages incellular communications communicated from the source to the cellulartransceiver. The messages can include one or more instructions (e.g.,unlocking the vehicle's doors), and the controller can instruct one ormore vehicle components to implement the instructions in the messages.While in the cellular mode, the controller can also returnacknowledgments of received messages by communicating the acknowledgmentin cellular communications from the cellular transceiver to the source.If the controller determines that the satellite receiver is to be used,the controller operates in a satellite mode to receive messages insatellite communications communicated from the source to the satellitereceiver. In the satellite mode, the controller can store anyacknowledgments of the received messages and can return the storedacknowledgments in cellular communications communicated from thecellular transceiver to the source when the cellular transceiver is tobe used.

In addition to determining whether to use the cellular or satellitefunctionalities, the controller can control the power consumption of abattery coupled to the Telematics unit. For example, the controller candetermine if the vehicle's ignition is turned off. Then, when theignition is off, the controller can programmably control power from thebattery to fee cellular transceiver and the satellite receiver. Toprogrammably control power to the cellular transceiver, for example, thecontroller can receive a discontinuous reception parameter from thecellular network with the cellular transceiver and can control thesupply of battery power to the cellular transceiver based on thediscontinuous reception parameter. To programmably control power to thesatellite receiver, for example, the controller can obtain on and offtimes designated for operating the satellite receiver and can controlthe supply of battery power to the cellular transceiver based on thosedesignated on and off times. As part of the programmable control, thecontroller can program a plurality of timers to track on and off statesin which the satellite receiver is operated and can compare those timersto the on and off times designated for operating the satellite receiver.Alternatively, the controller can obtain a total allowable durationdesignated for powering the satellite receiver while the ignition isoff. Then, the controller can allow the battery power to be supplied tothe satellite receiver for only the total allowable duration.

The foregoing is not intended to summarize each potential embodiment orevery aspect of the present disclosure. Let us now refer to the figuresto describe the subject matter of the present disclosure in detail.

Referring to FIG. 1, an embodiment of a Telematics system 10 accordingto certain teachings of the present disclosure is schematicallyillustrated. The Telematics system 10 includes a Telematics serviceprovider 29 and a Telematics unit 100, which in the present embodimentare vehicle-based. Although described as vehicle-based in the presentdisclosure, one skilled in the art will appreciate that the teachings ofthe present disclosure are not limited to such vehicle-based Telematicssystems but may also apply to other implementations where both cellularand satellite Telematics services are desirable.

The Telematics service provider 20, as its name indicates, providesTelematics services for the vehicle. To provide theses services, theTelematics service provider 20 has a communication link 23 with awireless or cellular network 30 and has another communication link 24with a satellite network 40. Details related to the communication links23 and 24 between the Telematics service provider 20 and the networks 30and 40 will be evident to those skilled in the art and are not describedin detail herein. Briefly, however, the cellular network 30 can includeany of a number of standard cellular communication networks, publicswitched telecommunication network (PSTN), the Internet, and integratedservices digital networks (ISDN). The satellite network 40 can use oneor more communication satellites.

Using the networks 30 and 40, fee Telematics service provider 20provides Telematics applications and services to the Telematics unit100. For example, the service, provider 20 may have operators, servers,and databases. The servers for the Telematics applications and servicescan include traffic servers, map servers, user profile servers, locationinformation servers, and the like. The databases for the Telematicsapplications and services can have location information, user profiles,traffic content, map content, point-of-interest content, usage history,and the like.

The Telematics unit 100 includes a controller 110, a network accessdevice 130, and a satellite device 140. In the present embodiment, thecontroller 110, network access device 130, and satellite device 140 areshown as somewhat independent. For example, the controller 110 has aprocessor 112 and memory 114, the network access device 130 has its owncontroller 132 and a cellular transceiver 134, and the satellite device140 has its own controller 142 and a satellite receiver 144. Althoughthe Telematics unit 100 is schematically shown as an integrated unit, itwill be appreciated that the controller 110 can be an independentcomponent external from the network access device 130 and satellitedevice 140, which can be independent of one another. In addition, thenetwork access device 130 and satellite device 140 may not have theirown controller 132 and 134. Instead, the controller 110 can be a unitarycontroller for the unit 100 and one or both of the cellular transceiver132 and satellite receiver 142, for example.

The Telematics unit 100 is communicatively coupled to a bus 150 of thevehicle (not shown) in which the unit 100 is installed and can have auser interface 152. The Telematics unit 100 is also communicativelycoupled to vehicle components 182, an ignition 184, and a power supplyor main battery 186. The vehicle components 182 can include door locks,lights, entertainment system, navigation system, communication system,and various automated or electronic devices found in a vehicle. Thevehicle bus 150 can be a data bus of the vehicle, an On-Board Diagnostic(OBD) connection, or the like. The power supply 186 includes a vehiclebattery that is used to power the Telematics unit 100, especially whenthe vehicle's ignition 184 is off.

The network access device 130 is used for transmitting uplinkcommunications to and receiving downlink communications from the serviceprovider 20 over cellular or wireless communication links. In this way,the Telematics system 10 can use existing cellular or wirelesscommunications links to provide traditional Telematics services (e.g.,unlocking vehicle doors, etc.) to the Telematics unit 100. The networkaccess device 130 can be based on Advanced Mobile Phone Service (AMPS),Global System for Mobile Communications (GSM), Time Division MultipleAccess (TDMA), Code Division Multiple Access (CDMA), (WCDMA), or otherprotocols. To transmit data in the cellular environment, different typesof standard bearer services exist including, but not limited to, generalpacket radio service (GPRS), short message service (SMS), circuitswitched data service (CSD), and high-speed circuit switched dataservice (HSCSD). In another embodiment, standard transmission controlprotocol/internet protocol (TCP/IP) may also be used.

In one embodiment, the Telematics unit 100 preferably uses the cellularfunctionality of the network access device 130 as its main link toreceive and send cellular communications with the service provider 20,and the satellite device 140 is used as a secondary or redundantcommunication channel to receive downlink communications from theservice provider 20 sent to the vehicle from the satellite network 40.Preferably, the satellite functionality is used if the network accessdevice 130 is not capable of communicating with the cellular network 30and/or is not preferred. For example, the Telematics unit 100 in thevehicle may be out of range of any cellular coverage of the cellularnetwork 30, the network access device 130 may fail to establish a linkfor whatever reason, or cellular communications may be congested orexpensive. Instead of using the cellular functionality, the Telematicssystem 10 can use satellite communication links to provide traditionalTelematics services (e.g., unlocking vehicle doors, etc.) to the vehiclein these types of situations.

During operation, for example, the network access device 130 is poweredand is used to receive any of the communications from the serviceprovider 20 via the cellular network 30 and its wireless antenna 138. Atcertain points or intervals, however, the controller 110 preferablydetermines if the network access device 130 is capable of communicatingwith the cellular network 30 (e.g., whether the vehicle is out of rangeof cellular coverage, the network access device 130 is not functioning)and/or whether using the cellular network 30 is preferred (e.g., thenetwork 30 is congested, use of the network 30 would be expensive fromthis location, etc.). If the network access device 130 is capable ofcommunicating with the cellular network 30 and/or it is preferred, thecontroller 110 waits for messages in cellular or wireless communicationsfrom the service provider 20. The messages can include instructions orcommands to be implemented by vehicle components 182.

When a message is received, the controller 110 processes the receivedmessages and instructs the corresponding vehicle components 182 toimplement the instructions of the received message. After execution, thecontroller 110 configures an acknowledgment that the message has beenreceived and/or that the instructions in the messages have or have notbeen successfully performed. The controller 110 can also access anystored acknowledgments from previous messages that have yet to betransmitted. Finally, the controller 110 accesses the cellulartransceiver 130 and returns the one or more acknowledgments to theservice provider 20 via the cellular network 30. Of course, beforereturning the acknowledgments, the controller 110 may again determine ifthe cellular transceiver 130 is still capable of communicating with thecellular network 30 and/or if it is preferred. If not, the controller110 can instead store the configured acknowledgements for sending later.

If the network access device 130 is determined to be incapable ofcommunicating with the cellular network 30 or is not preferred forwhatever reason, however, the Telematics unit 100 instead uses thesatellite functionality. For example, the cellular service provided bythe cellular network 30 at a given point during operation may be overlycongested, restrictive, or expensive. Alternatively, the network accessdevice 130 may simply be out of range of the cellular network 30. Insuch a situation, the controller 110 powers up the satellite device 140,if not already powered, and waits for a message in a satellitecommunication communicated from the service provider 20 via thesatellite network 40. For its part, the service provider 20 mayinitially attempt to send a message in a cellular communication to theTelematics unit 100 via the cellular network 30. When an acknowledgmentto that cellular communication has not been received from the Telematicsunit 100 in a certain time period because the Telematics unit 100 isactually out of cellular coverage, for example, then the serviceprovider 20 then sends the message in a satellite communication to theTelematics unit 100 via the satellite network 40.

When the satellite device 140 receives the message in the satellitecommunication, the controller 110 processes the received message andinstructs the vehicle components 182 to implement the instructions inthe message. Finally, the controller 110 configures an acknowledgment ofthe message and/or its successful implementation and stores theacknowledgment so it can be returned later to the service provider 20with the network access device 130. When the vehicle returns to an areawith cellular coverage, for example, the stored acknowledgement can besent back to the Telematics service provider 20 for positiveconfirmation. The acknowledgments of the messages received in thesatellite communications are returned later using the network accessdevice 130 because the Telematics unit 100 in the present embodiment hassatellite receiver 144 as opposed to having a satellite transceivercapable of sending and receiving satellite communications. However, inan alternative embodiment, the Telematics unit 100 can include asatellite transmitter in addition to the satellite receiver 144 so theTelematics unit 100 can return the acknowledgments in satellitecommunications via satellite communications.

The Telematics unit 100 in the vehicle can be operated when the vehicleis running or not running (i.e., when the ignition 184 is on or off).When the vehicle ignition 184 is “on” the Telematics unit 100 canoperate with either one or both of the cellular and satellitefunctionalities without significant concerns about power consumption.Consequently, the network access device 130 may be continuously poweredwhile the vehicle is “on,” and the satellite device 140 can also becontinuously powered or can be freely powered up when needed.

When the vehicle ignition 184 is “off,” however, the Telematics unit 100preferably operates efficiently by addressing issues of powerconsumption caused by both monitoring and operating the combinedcellular and satellite functionalities. In the present embodiment, theTelematics unit 100 includes a main power supply 116, one or moreprogrammable timers 160, a monitor 170, a transceiver power supply 136,and a receiver power supply 146, each of which are used to address thepower consumption by the Telematics unit 100. The various power supplies116, 136, and 146 of the unit 100 are electrically connected to the mainbattery 186 of the vehicle and are used respectively to control thesupply of power and to convert the voltage from the battery 186 tovoltages for the controller 110, network access device 130, andsatellite device 140.

The controller 110 provides the programmable timers 160 with informationon when the power to the transceiver 134 and receiver 144 should beenabled and disabled. In turn, the power supplies 136 and 146 receiveinputs from the programmable timers 160 and control the supply ofbattery power to the transceiver 134 and receiver 144, respectively. Theprogrammable timers 160 can include circuitry separate from thecontroller 110. Alternatively, the programmable timers 160 can be partof or otherwise integrated into the controller 110.

If the vehicle is on, then the network access device 130 and satellitedevice 140 can both be powered and operated at the same time because thedevices 130 and 140 can both be supplied with sufficient power. However,when the vehicle ignition 184 is turned off, it may be necessary for theTelematics unit 100 to monitor and control the power consumption. Abrief explanation of how the Telematics unit 100 monitors and controlspower consumption is discussed here and additional details will beexplained later.

Initially, the controller 110 receives a signal that the vehicle'signition 184 has been turned off. The controller 110 can operate thenetwork access device 130 and the satellite device 140 in powered statesin at least two modes: a continuous power mode and a periodic powermode. In the continuous power mode, for example, the circuitry for atleast the receiving portions of the cellular transceiver 134 or thesatellite receiver 144 can be continuously supplied with power from thebattery 186 through the power supply 136 or supply 146, respectively. Ina periodic power mode, the circuitry for at least the receiving portionsof the cellular transceiver 134 or the satellite receiver 144 can beperiodically supplied with power from battery 186 through the powersupply 136 or supply 146, respectively.

For the periodic power mode, the controller 110 can determine on/offduty cycles for the power supplies 136 and 146. In one embodiment, thecontroller 110 determines the on/off duty cycles for the network accessdevice 130 based on a discontinuous reception (DRX) parameter receivedfrom the cellular network 30. The on/off duty cycles for the transceiverpower supply 136 are sent to the programmable timers 160, and theprogrammable timers 160 then use the duty cycles to disable and enablethe transceiver power supply 136. In one embodiment, the controller 110determines on/off duty cycles for the programmable timers 160 used todisable/enable the power supply 146 to the satellite device 140. Theon/off duty cycles for the receiver power supply 146 can be based onpreset on/off times stored in memory 114 and know to the serviceprovider 20.

As noted above, the on/off duty cycles for the programmable timers 160used to disable/enable the power supply 136 to the network access device130 can be based on a discontinuous reception (DRX) parameter receivedfrom the cellular network 30. Discontinuous reception allows theTelematics unit 100 to power down significant amounts of its internalcircuitry for a high percentage of time when the unit 100 is idle.Discontinuous reception also allows the Telematics unit 100 to know whenpage requests from the service provider 20 directed to the unit 100 maybe transmitted via the cellular network 30. For example, the Telematicsunit 100 can “sleep” during times that it knows that its paging requestswill not be transmitted. When the Telematics unit 100 enters aparticular paging area, the cellular transceiver 134 obtains a parameterfrom the cellular network 30 as part of the registration process. Theparameter is then used by the controller 110 and other applications tocontrol power to the cellular transceiver 134 while the vehicle ignition184 is off.

The parameter from the cellular network 30 tells the network accessdevice 130 how often to “wake up” and to process a page in the area ofcellular coverage. In GSM networks, for example, a discontinuousreception factor (or “DRX factor”) can be used to notify the unit 100 ofthe paging repetition rate within a particular area. The DRX factor isbroadcast in the Broadcast Control Channel (BCCH). A low value for theDRX factor indicates that the unit 100 should check for paging messageswith a greater frequency, while a high value for the DRX factorindicates that the network access device 30 should check for the pagingmessages with a lower frequency. In general, checking with greaterfrequency reduces the delay in setting up an incoming message but hasthe downside of draining the battery 186 quicker. By contrast, checkingwith lower frequency reduces the draining of the battery 186 but has thedownside of further delaying the setup of an incoming message.

In addition to controlling the power supplies 136 and 146 with theprogrammable timers 160 and duty cycles, the Telematics unit 100 can usepower saving techniques such as disclosed in U.S. Patent Publications2004/0127265 to Von Bosch et al. and 2004/0127206 to Van Bocsh et al.,which are both incorporated herein by reference. For example, thenetwork access device 130 and satellite device 140 can monitor thevoltage level of the battery 186 and can control the power supplies 136and 146 if a low battery voltage is detected. In another example, themonitor 170 can be used to monitor the current levels, which theprogrammable timers 160 can then use to control the power supplies 136and 146 if an excessive accumulated drawn current is detected.

Now that details of the Telematics system 10 have been discussed, we nowturn to a discussion of how the Telematics system 10 operates. Referringto FIG. 2, a process 200 of operating the Telematics system, isillustrated in flowchart form. In the discussion that follows, referenceis concurrently made to element numerals for components of FIG. 1.

Initially, the controller 110 of the Telematics unit 100 determines ifthe vehicle's ignition 184 is “on” (Block 202). If so, the Telematicsunit 100 preferably functions in a normal mode (Block 204). In thisnormal mode, both the network access device 130 and the satellite device140 can remain operational at the same time and can be used to monitorfor communications from the Telematics service provider 20 via shecellular network 30 and/or the satellite network 40. The functionsimplicated in a received message can be performed, and acknowledgmentscan be resumed via the cellular network 30.

When the vehicle's ignition 184 is determined to be “off” at Block 202,the Telematics system 10 preferably functions in a power save mode andsets a search duration timer (Block 206). The search duration timer is apreset length of time in which the Telematics unit 100 will attempt toestablish a connection with either of the networks 30 and 40. Ifconnection cannot be established with either network 30 and 40 withinthe time limit of the duration timer, the Telematics unit 100 preferablypowers down both the network access device 130 and satellite device 140to conserve the vehicle's battery 186.

After setting the search duration timer, the Telematics unit 100 candetermine whether the battery 186 has a low voltage level, which can becaused by any of a number of reasons (Block 206). Checking the batterylevel and shutting off the devices 130 and 140 can be performed at mypoint in the operation of the Telematics unit 100 but has been shownhere as part of the initial steps.

Discussion briefly turns to a process of checking the battery 186coupled to the Telematics unit 110 illustrated in FIG. 3. In the batterychecking process 300, the controller 110 first determines whether it isoperating on a main or backup battery in the vehicle (Block 302). Ifoperating from the main battery, the controller 110 sets a low batterythreshold to the limits of the main battery (Block 310). If operatingfrom the backup battery, the controller 110 sets the low batterythreshold to the limits of the backup battery (Block 328). In eithercase, the controller 110 determines from the current monitor 170 of theunit 100 whether the battery level is below the set threshold (Block330). If so, the controller 110 preferably switches the network accessdevice 130 and the satellite receiver 140 to a power-off state topreserve power in this circumstance. Otherwise, the controller 110returns to its current operation (Block 350).

We now return to FIG. 2 to continue our discussion of how the Telematicsunit 100 operates to conserver battery power. After determining that thebattery 186 is not low at Block 210, the Telematics unit 100 powers upthe network access device 130 (if not already on) and turns off thesatellite device 140 (if not already off) (Block 212). When powered up,the network access device 130 determines whether the cellulartransceiver 134 is capable of communicating with the cellular network 30(e.g., whether the transceiver 134 is within cellular coverage of thenetwork 30) (Block 214).

If so, then the Telematics unit 100 operates the network access device130 according to a power mode scheme, monitors for messages in cellularcommunications, and performs functions in received messages (Block 220).The messages communicated to the vehicle are preferably encrypted usingknown encryption techniques known in the art. The messages can bespecific to a vehicle or can be sent to “group” of vehicles.

For the power mode scheme, the cellular transceiver 134 can be turned oncontinuously only for a programmable amount of time, or it can be turnedon and off periodically according to on/off duty cycles. In oneembodiment discussed previously, the Telematics unit 100 can uses DRXtechniques disclosed herein and disclosed in the incorporated U.S.patent Publications 2004/0127265 and 2004/0127206 to control when toturn the cellular transceiver 134 on and off. When turned on, thecellular transceiver 134 monitors for messages in cellularcommunications, implements any functions or instructions contained inthose messages, and returns acknowledgments according to the techniquesdisclosed herein. One embodiment of a process of operating the networkaccess device 130 with a power mode scheme is discussed below withreference to FIG. 4. At any point while operating the network accessdevice 130, the Telematics unit 100 can determine whether the cellulartransceiver 134 is still capable of communicating with the cellularnetwork 30 by returning to Block 214.

If the cellular transceiver 134 is initially or subsequently incapableof communicating with the cellular network 30 for whatever reason whilethe vehicle's ignition 184 is still off, the Telematics unit 100 powersdown the network access device 130 and instead powers up the satellitedevice 140 (Block 216). If the satellite device 140 includes its owncontroller 142 as in the embodiment of FIG. 1, then the satellite device140 determines whether the satellite receiver 144 is capable ofcommunicating with a satellite network 40. Otherwise, the maincontroller 110 of the Telematics unit 100 can perform this function.

Satellite coverage may be blocked or unavailable for any number ofreasons. If the satellite receiver 144 is incapable of receivingcommunications from the satellite network 40, then the Telematics unit100 determines whether the search duration timer—initially set at Block206—has expired (Block 240). If so, then the Telematics unit 100 powersdown both the network access device 130 and the satellite device 140indefinitely to conserver battery power (Block 242). For example, thevehicle having the Telematics unit 100 may be parked for an extendedperiod of time in a basement garage where neither cellular or satellitecoverage is available. Therefore, it is desirable in such a situation tostop attempting to establish communications with the cellular andsatellite networks 30 and 40 while the vehicle ignition 184 remains off.If, on the other hand, the search duration timer has not expired atBlock 240, the process 200 can return to previous steps such as checkingthe battery to determine if it has a low voltage (Block 210).

If the satellite receiver 144 is capable of receiving satellitecommunications at Block 218, then the satellite device 140 is operatedwith a power mode scheme so it can establish communications with thesatellite network 40, receive messages in satellite communications, yetstill conserver battery power. An embodiment of a process of operatingthe satellite device 140 is discussed below with reference to FIG. 5. Toconserver battery power, the Telematics unit 100 can use a number oftechniques for the power mode scheme while operating the satellitereceiver 144. In one power mode scheme discussed below with reference toFIG. 6C, the satellite receiver 144 can be turned on continuously onlyfor a programmable amount of time (e.g., one hour). In other power modeschemes discussed below with reference to FIGS. 6A-6B, the satellitereceiver 144 can be programmed to wakeup periodically and then go tosleep for programmable amounts of time to conserve the vehicle's battery186. When powered up, the satellite receiver 144 awaits incomingmessages.

To reduce the current drain on the battery 186, the satellite receiver144 can be turned on at preset or know times so that the serviceprovider 20 can know when the Telematics unit 100 in the vehicle withthe ignition 184 off will be most likely to receive a satellitecommunication. For example, the Telematics unit 100 can decode the timefrom a GPS receiver (not shown) that is coupled to the unit 100. Usingthe decoded time, the Telematics unit 100 can power up the satellitereceiver 144 at precise time intervals according to preset times storedin memory. This time interval could be programmable (short or longdelays). The time interval when the satellite receiver 144 is on wouldbe known by design by the service provider 20. Thus, the serviceprovider 20 would know when the Telematics unit 100 in the vehicle wouldbe on and would be capable of receiving a message from the serviceprovider 20 (e.g., unlock the doors or flash the lights) via thesatellite network 40. When a message in a satellite communication isreceived, the Telematics unit 100 implements the functions in themessage and configures an acknowledgement indicating whether thefunction has been successfully implemented or not.

Preferably, the Telematics unit 100 operates the satellite receiver 144(either continuously or intermittently) for only a predetermined amountof time. Accordingly, the Telematics unit 100 checks whether thepredetermined amount of time has expired (Block 232). If not, then theprocess can return to operating the satellite device 140. Otherwise, theprocess 200 returns to Block 210 to eventually determine if the battery186 is low and to determine whether cellular converge is available orimproved.

As noted previously at Block 220 of FIG. 2, the network access device130 is preferably operated with a power mode scheme to conserve batterypower when the vehicle's ignition 184 is “off.” Turning to FIG. 4, aprocess 400 of operating the network access device 140 to conserverbattery power is illustrated in flow chart form. After determining thatthe network access device 130 is in cellular coverage (Block 214), thecontroller 110 resets the search duration timer that was initially setat Block 206 of FIG. 2 (Block 402). Additionally, the controller 110resets power mode timer(s) to default values (Block 406). These powermode timers are part of the one or more programmable timers 160 of theTelematics unit 100 discussed previously. The power mode timers areultimately used to conserve battery power by limiting the amount of timethe transceiver 134 and receiver 144 can search for signals, can remainidle awaiting messages, or can remain powered up from the time that theignition 184 was turned off. The power mode timers may be programmableand may change during operation of the Telematics unit 100 ascircumstances, such as cellular and satellite coverage, changes.Therefore, the default values would represent the preset orpredetermined values initially stored within the unit 100.

Next, the controller 110 determines whether a flag has been previouslyset for any acknowledgments of previous messages that could not be sentvia the cellular network 30. If the flag exists, the controller 110instructs the network access device 140 to transmit the storedacknowledgments to the service provider 20 (Block 410), and thecontroller 110 clears the flag (Block 412).

If no flag was set or if the flag is cleared, the Telematics unit 100then monitors the cellular link for messages using the DRX techniquesand schemes disclosed herein, and the Telematics unit 100 performs thefunctions contained in any of the received messages (Block 414). Afteroperating according to the DRX techniques in Block 414 for apredetermined amount of time, the network access device 130 determinesif it is still in cellular coverage (Block 416). If so, the unit 100 cancontinue monitoring for messages in cellular communications. Otherwise,the process returns to Block 216 of FIG. 2 so the cellular transceiver134 can be turned off and the satellite receiver 144 can be turned on.

As noted previously at Block 230 of FIG. 2, the satellite device 130 isalso preferably operated with a power mode scheme to conserve batterypower when the vehicle's ignition 184 is “off.” Turning to FIG. 5, aprocess 500 of operating the satellite device 140 to conserver batterypower is illustrated in flow chart form. After determining that thesatellite device 140 is in satellite coverage (Block 218), thecontroller 110 resets the search duration timer that was initially setat Block 206 of FIG. 2 (Block 502). Additionally, the controller 110resets the power mode timer(s) to default values as discussed previously(Block 504).

Then, the Telematics unit 100 uses a satellite power mode scheme tocontrol the satellite device 140 and to conserve battery power.Embodiments of power mode schemes for the satellite device 140 arediscussed below with reference to FIGS. 6A through 6C. In general, thesepower mode schemes limit the total duration of time that the satellitereceiver 144 is allowed to remain on and continue searching forsatellite communications or satellite coverage. In addition, these powermode schemes control when and for how long the satellite receiver 144may be turned on and off.

After initiating the power mode scheme, the satellite device 140determines whether it is still in satellite coverage (Block 508). Ifnot, the process 500 returns to block 240 of FIG. 2 to determine if thetotal search duration has expired. If the device 140 is in satellitecoverage, however, the satellite receiver 144 monitors the satellitelink for messages from the service provider 20 and performs thefunctions contained in those messages when received (Block 510). Inaddition, any acknowledgments for received messages are preferablystored in memory and a flag is set so the stored acknowledgment can besent later by the unit 100 when cellular communication is possible.

After a predetermined amount of time of monitoring the satellite link,the Telematics unit 100 determines whether if is time to cheek forcellular coverage (Block 512). If a cellular link cannot be established,the process 500 returns to Block 506 to use the satellite power modescheme to conserving the battery power. If a cellular link can beestablished, then the process 500 returns to Block 206 of FIG. 2 tocheck the power level of the vehicle's battery 186 and subsequently tocheck for cellular coverage.

In FIG. 6A, a first power mode scheme 600 for operating the satellitereceiver 144 is illustrated in flow chart form. As noted above, thepower mode scheme 600 is initiated at Block 506 of FIG. 5. This firstpower mode scheme 600 uses programmed DRX on/off times to control whento turn on and off the satellite receiver 144. Initially, the DRX on/offtimes for the satellite receiver 144 are read from programmable memory(Block 602), and the total allowable duration of operating the satellitereceiver 144 is read from programmable memory (Block 603). If thesatellite device 140 is capable of implementing DRX under its owncontrol (e.g., the satellite device 140 has controller 142 capable ofDRX), then the controller 142 can read the on/off times from aprogrammable memory (not shown) of the satellite device 140. On theother hand, if the satellite device 140 receives DRX control externally(e.g., the main controller 110 gives external control), then theprocessor 112 of the controller 110 reads the on/off times from itsprogrammable memory 114. The on/off times are used to control when thesatellite receiver 144 is turned on and off to monitor for messages insatellite communications from the service provider 20.

After reading the above information, the Telematics unit 100 checks thebattery according to the techniques disclosed above (Block 604) anddetermines whether the total allowable duration for operating thesatellite receiver 144 has expired (Block 606). If the duration hasexpired, the satellite receiver 144 is powered off (if not already)(Block 608) and operation essentially returns to Block 242 of FIG. 2where both the satellite receiver 144 and the cellular transceiver 134are turned off because the total allowed time to search for coverage hasexpired (Block 610).

If the total allowable duration for operating the satellite receiver 144has not expired at Block 606, however, the controller 110/142 determinesif the satellite receiver 144 is on (Block 612). If it is on, thecontroller 110/142 determines from the stored on/off times if it is timeto turn off the satellite receiver 144 (Block 614). If so, the receiver144 is turned off (Block 616), and operation returns to Block 512 ofFIG. 5 to determine whether it is time to check if the cellulartransceiver 134 is in cellular coverage (Block 618). If it is not yettime to turn off the receiver 144, operation returns to Block 508 ofFIG. 5 to continue monitoring for messages (Block 620).

Similarly, if the satellite receiver 144 is not on at Block 612, thecontroller 110/142 determines if it is time to turn on the satellitereceiver 144 based on the on/off times read from memory (Block 622). Ifit is time to turn on, the receiver 144 is turned on (Block 624), andoperation returns to Block 508 of FIG. 5 to monitor for messages (Block620). If the receiver 144 is not on and it is not yet time to turn it onat Block 622, then operation returns to Block 512 of FIG. 5 to determinewhether it is time to check if the cellular transceiver 134 is incellular coverage (Block 618).

In FIG. 6B, a second power mode scheme 630 for operating the satellitereceiver 144 is illustrated in flow chart form. Again, this power modescheme 630 is initiated at Block 506 of FIG. 5 and uses programmed DRXon/off times to control when to turn on and off the satellite receiver144. Initially, the on/off times for the satellite receiver 144 and thetotal allowable duration of operating the satellite receiver 144 areread from programmable memory in either the satellite device 140 orcontroller's programmable memory 114 (Blocks 632 & 633). After readingthe on/off time, the Telematics unit 100 checks the battery according tothe techniques disclosed above (Block 634).

Next, the Telematics unit 100 controls supply of power from the battery186 to the satellite receiver 144 based on the designated DRX on/offtimes read from memory. These designated on/off times may bepreconfigured or preset times, for example, and the Telematics unit 100can determine current time from a GPS receiver, internal clock, or otherdevice to determine when current time corresponds to one of thedesignated on/off times. Using the on/off times, a plurality of timers160 can be programmed to track the on/off states in which the satellitereceiver 144 is operated in comparison to the on/off times designatedfor operating the satellite receiver 144. These timers 160 can include(T_SAT_ON) that indicates a current amount of time that the satellitereceiver 144 has been on; (T_SAT_ON_MAX) that indicates a maximum amountof time that the satellite receiver 144 is permitted to be on since theignition 184 has been turned off; (T_SAT_DRX) that indicates a currentamount of time that the satellite receiver 144 has been on in a currenton/off or DRX time period; (T_SAT_DRX_ON) that indicates an amount oftime that the satellite receiver 144 is to be on in each on period; and(T_SAT_DRX_OFF) that indicates an amount of time that the satellitereceiver 144 is to be off in each off period.

Using these timers 160 during operation, the Telematics unit 100determines whether the current amount of time that the satellitereceiver 144 has been on (T_SAT_ON) meets or exceeds the maximum amountof time that she satellite receiver 144 is permitted to be on(T_SAT_ON_MAX) (Block 636). If the receiver 144 has been on for as longas is allowed, the satellite receiver 144 is powered off (if notalready) (Block 638), and operation essentially returns to block 242 ofFIG. 2 so that no more battery power will be consumed by the Telematicsunit 100 while the vehicle's ignition 184 remains off (Block 640).

If the time that the satellite receiver 144 has been on is less than themaximum time limit at Block 636, the controller 110/142 determines ifthe satellite receiver 144 is on (Block 642). If it is on, thecontroller 110/142 determines if the current amount of DRX time that thesatellite receiver 144 has been on in the current DRX period (T_SAT_DRX)meets or exceeds the amount of time that the satellite receiver is to beon in each DRX period (T_SAT_DRX_ON) (Block 644). If so, the currentamount of DRX time that the satellite receiver 144 has been on(T_SAT_DRX) is set to 0 (Block 645), the DRX receiver 144 is turned off(Block 646), and operation returns to Block 512 of FIG. 5 to determinewhether it is time to check if the cellular transceiver 134 is incellular coverage (Block 648). If the receiver 144 is on but it is notyet time to turn it off, then operation returns to Block 508 of FIG. 5so that the receiver 144 can continue to monitor for messages (Block650).

Similarly if the receiver 144 is not on at Block 642, the controller110/142 determines if the current amount of DRX time that the satellitereceiver 144 has been off in this current DRX period (T_SAT_DRX) meetsor exceeds the amount of time that the satellite receiver 144 is set tobe off in each DRX period (T_SAT_DRX_OFF) (Block 652). If it is timethen to turn on the receiver 144, the current amount of DRX time thatthe satellite receiver 144 has been off (T_SAT_DRX) is set to 0 (Block653), the receiver 144 is turned on (Block 654), and operation returnsto Block 508 of FIG. 5 so the receiver 144 can monitor for messages(Block 650). If the receiver 144 is not on and it is not yet time in theDRX period to turn it on at Block 652, operation instead returns toBlock 512 of FIG. 5 to determine whether it is time to check if thecellular transceiver 144 is in cellular coverage (Block 648).

In FIG. 6C, a third power mode scheme 660 for operating the satellitereceiver 144 is illustrated in flow chart form. This power mode scheme660 is used when the satellite receiver 144 is to be poweredcontinuously for a programmable duration and is not periodically turnedon and off. In this scheme 660, the total allowable time duration forthe satellite receiver 144 to be on is read from programmable memory(Block 662). The battery level is then checked using the techniquesdisclosed herein (Block 664), and a determination is made whether thetotal allowable time duration has expired (Block 666). If so, thesatellite receiver 144 is powered off (Block 669). Otherwise, the schemereturns to Block 508 of FIG. 5 so the receiver 144 can continuemonitoring for messages (Block 670).

As alluded to above, a number of programmable timers 160 in FIG. 1 canbe used to conserve power of the battery 186. For the programmabletimers 160, the Telematics unit 100 can compare running values to presetvalues, limits, or thresholds to trigger when to turn on/off thecellular transceiver 134 or the satellite receiver 144 or to performsome other action to conserve the battery 186. For example, the SearchDuration Timer discussed previously can be used to track how much timehas elapsed since the last time the cellular transceiver 134 or thesatellite receiver 144 was in coverage. The Search Duration Timer can becompared to a number of preset values or limits to determine if theTelematics unit 100 should continue or stop searching for coverage. Forexample, the Search Duration Timer can be compared to a preset Tsearchvalue that represents the maximum allotted time to search in oneinstance of no cellular service for either or both of the transceiver134 or the receiver 144. The Tsearch value can indicate that if nosignal has been received from either the cellular network 30 or thesatellite network 40 for a preset amount of time (e.g., 10 minutes),then the Telematics unit 100 can assume the vehicle has no visibility toeither network 30 and 40 and can power down both the transceiver 134 andreceiver 144.

Additional preset values can be used in conjunction with programmabletimers 160 in FIG. 1 to track and control operation of the Telematicsunit 100 to conserve the battery 186. In one example, a Tcellular_searchvalue can represent the maximum total time, measured from the time theignition 184 is turned off, for the cellular transceiver 134 to bepowered in a “No Service” state. Current drain on the battery 186 whilethe cellular transceiver 134 is searching for service may be very highcompared to an idle mode of operation. Accordingly, a running timer 160can be compared to the Tcellular_search value to limit the total timethat the cellular transceiver 134 searches in a “No Service” state so asnot to drain the vehicle battery 186.

In another example, a Tcellular_idle value can represent the maximumtotal time, measured from the time the ignition 184 is turned off, forthe cellular transceiver 134 to be powered in the “Idle” state. Currentdrain in the idle state may be lower than in the search state. However,it is still preferable that a running timer 160 is compared to theTcellular_idle value to limit the total time the cellular transceiver134 is powered in the Idle state so as not to drain the vehicle battery186.

In yet another example, a Tsat_search value can represent the maximumtotal time, measured from the time the ignition 184 is turned off, forthe satellite receiver 144 to be powered without acquiring a satellitesignal. Current drain in the search mode of the satellite receiver 114can be very high. Consequently, a running timer 160 can be compared tothe Tsat_search value to limit the total time in the satellite receiver144 searches so as not to drain the vehicle battery 186.

In a final example, a Tsat_idle value can represent the maximum totaltime, measured from the time the ignition 184 is turned off, for thesatellite receiver 144 to be powered in an idle state to receivesatellite communications. Again, a running timer 160 can be compared tothe Tsat_idle value to limit the total time the satellite receiver 144is idle so as not to drain the vehicle battery 186. One skilled in theart will appreciate that these and other values and timers 160 can beused to track and control operation of the Telematics unit 100 toconserve the battery 186.

The foregoing description of preferred and other embodiments is notintended to limit or restrict the scope or applicability of theinventive concepts conceived of by the Applicants. In exchange fordisclosing the inventive concepts contained herein, the Applicantsdesire all patent rights afforded by the appended claims. Therefore, itis intended that the appended claims include all modifications andalterations to the full extent that they come within the scope of thefollowing claims or the equivalents thereof.

1. A system, comprising: a cellular transceiver for communicatingcellular communications with a source of Telematics service via acellular network; a satellite receiver for receiving satellitecommunications from the source via a satellite network; and at least onecontroller communicatively coupled to the cellular transceiver and thesatellite receiver and configured to control the cellular transceiverand the satellite receiver to establish communication with the sourceusing either one or both of the cellular network and the satellitenetwork, the at least one controller configured to determine whether touse the cellular transceiver or the satellite receiver to communicatewith the source, wherein if the cellular transceiver is determined to beused, the at least one controller is configured to operate in a cellularmode and is configured to receive a message in a first cellularcommunication communicated from the source to the cellular transceiver,wherein if the satellite receiver is determined to be used, the at leastone controller is configured to operate in a satellite mode and isconfigured to receive a message in a first satellite communicationcommunicated from the source to the satellite receiver, and wherein theat least one controller is further configured to: configure anacknowledgment that the message received in the first satellitecommunication has been received in the satellite mode; and return, in asecond cellular communication communicated, when the cellulartransceiver is determined to be used, from the cellular transceiver tothe source, the acknowledgment that the message has been received in thesatellite mode; wherein the at least one controller is operativelycoupled to a battery, and wherein the at least one controller isconfigured to: determine if a vehicle is turned off, and programmablycontrol power from the battery to the cellular transceiver when thevehicle is turned off; and wherein to programmably control power fromthe battery to the cellular transceiver, the at least one controller isconfigured to: receive a discontinuous reception parameter from thecellular network with the cellular transceiver; and control supply ofpower from the battery to the cellular transceiver based on thediscontinuous reception parameter.
 2. The system of claim 1, wherein todetermine whether to use the cellular transceiver or the satellitereceiver to communicate with the source, the at least one controller isconfigured to determine one or more of whether the cellular transceiveris capable of communicating with the cellular network, whether thecellular transceiver is out of communication range of the cellularnetwork, whether the cellular network is congested, whether an expensefor using the cellular network exceeds a predetermined amount, andwhether using the cellular network is not preferred.
 3. The system ofclaim 1, wherein the message comprises one or more instructions, andwherein the at least one controller is configured to instruct one ormore vehicle components to implement the one or more instructions in themessage.
 4. The system of claim 1, wherein the at least one controllerin the cellular mode is further configured to return an acknowledgmentof the message in a second cellular communication communicated from thecellular transceiver to the source.
 5. A Telematics service method,comprising: establishing communication of a Telematics unit with asource of Telematics service using either one or both of a cellularnetwork and a satellite network; determining whether to use the cellularnetwork or the satellite network to communicate between the Telematicsunit and the source of Telematics service; if the cellular network isdetermined to be used, receiving a message in a first cellularcommunication communicated from the source to the Telematics unit withthe cellular network; if the satellite network is determined to be used,receiving the message in a first satellite communication communicatedfrom the source to the Telematics unit with the satellite network; andwherein the act of receiving the message in the first satellitecommunication communicated from the source to the Telematics unit withthe satellite network further comprises: configuring an acknowledgmentthat the message received in the first satellite communication has beenreceived in the satellite mode; returning, in a second cellularcommunication communicated, when the cellular network is determined tobe used, from the Telematics unit to the source, the acknowledgment thatthe message has been received in the satellite mode; determining if avehicle is turned off; programmably controlling power to the cellulartransceiver when the vehicle is turned off; wherein the act ofprogrammably controlling power to the cellular transceiver comprises:receiving a discontinuous reception parameter from the cellular network;and controlling supply of power to the cellular transceiver based on thediscontinuous reception parameter.
 6. The method of claim 5, the act ofdetermining whether to use the cellular network or the satellite networkto communicate between the Telematics unit and the source of Telematicsservice comprises determining one or more of: whether the cellulartransceiver is capable of communicating with the cellular network,whether the cellular transceiver is out of communication range of thecellular network, whether the cellular network is congested, whether anexpense for using the cellular network exceeds a predetermined amount,and whether using the cellular network is not preferred.
 7. The methodof claim 5, wherein the message comprises one or more instructions, andwherein the method further comprises instructing one or more vehiclecomponents to implement the one or more instructions in the message. 8.The method of claim 5, wherein the act of receiving the message to thefirst cellular communication communicated from the source to theTelematics unit with the cellular network further comprises returning anacknowledgment of the message in a second cellular communicationcommunicated from the Telematics unit to the source with the cellularnetwork.
 9. The system of claim 1, wherein the at least one controlleris further configured to configure the acknowledgment that the messagehas been received in the satellite mode to indicate that an instructionin the message has been successfully performed.
 10. The method of claim5, further comprising: configuring the acknowledgment that the messagehas been received in the satellite mode to indicate that an instructionin the message has been successfully performed.
 11. A system,comprising: a cellular transceiver for communicating cellularcommunications with a source of Telematics service via a cellularnetwork; a satellite receiver for receiving satellite communicationsfrom the source via a satellite network; and at least one controllercommunicatively coupled to the cellular transceiver and the satellitereceiver and configured to control the cellular transceiver and thesatellite receiver to establish communication with the source usingeither one or both of the cellular network and the satellite network,the at least one controller configured to determine whether to use thecellular transceiver or the satellite receiver to communicate with thesource, wherein if the cellular transceiver is determined to be used,the at least one controller is configured to operate in a cellular modeand is configured to receive a message in a first cellular communicationcommunicated from the source to the cellular transceiver, wherein if thesatellite receiver is determined to be used, the at least one controlleris configured to operate in a satellite mode and is configured toreceive a message in a first satellite communication communicated fromthe source to the satellite receiver, and wherein the at least onecontroller is further configured to: configure an acknowledgment thatthe message received in the first satellite communication has beenreceived in the satellite mode; and return, in a second cellularcommunication communicated, when the cellular transceiver is determinedto be used, from the cellular transceiver to the source, theacknowledgment that the message has been received in the satellite mode;wherein the at least one controller is operatively coupled to a battery,and wherein the at least one controller is configured to: determine if avehicle is turned off, and programmably control power from the batteryto the satellite receiver when the vehicle is turned off; and wherein toprogrammably control power from the battery to the satellite receiver,the at least one controller is configured to: obtain on and off timesdesignated for operating the satellite receiver; and control supply ofpower to the satellite receiver based on the designated on and offtimes.
 12. The system of claim 11, wherein to determine whether to usethe cellular transceiver or the satellite receiver to communicate withthe source, the at least one controller is configured to determine oneor more of whether the cellular transceiver is capable of communicatingwith the cellular network, whether the cellular transceiver is out ofcommunication range of the cellular network, whether the cellularnetwork is congested, whether an expense for using the cellular networkexceeds a predetermined amount, and whether using the cellular networkis not preferred.
 13. The system of claim 11, wherein the messagecomprises one or more instructions, and wherein the at least onecontroller is configured to instruct one or more vehicle components toimplement the one or more instructions in the message.
 14. The system ofclaim 11, wherein to control supply of power from the battery to thesatellite receiver based on the designated on and off times, the atleast one controller is configured to: program a plurality of timers totrack on and off states in which the satellite receiver is operated, andcompare the timers to the on and off times designated for operating thesatellite receiver.
 15. The system of claim 11, wherein to programmablycontrol power from the battery to the satellite receiver, the at leastone controller is configured to: obtain a total allowable durationdesignated for powering the satellite receiver; and control supply ofpower from the battery to the satellite receiver based on the totalallowable duration.
 16. The system of claim 11, wherein the at least onecontroller in the cellular mode is further configured to return anacknowledgment of the message in a second cellular communicationcommunicated from the cellular transceiver to the source.
 17. The systemof claim 11, wherein the at least one controller is further configuredto configure the acknowledgment that the message has been received inthe satellite mode to indicate that an instruction in the message hasbeen successfully performed.
 18. A Telematics service method,comprising: establishing communication of a Telematics unit with asource of Telematics service using either one or both of a cellularnetwork and a satellite network; determining whether to use the cellularnetwork or the satellite network to communicate between the Telematicsunit and the source of Telematics service; if the cellular network isdetermined to be used, receiving a message in a first cellularcommunication communicated from the source to the Telematics unit withthe cellular network; if the satellite network is determined to be used,receiving the message in a first satellite communication communicatedfrom the source to the Telematics unit with the satellite network; andwherein the act of receiving the message in the first satellitecommunication communicated from the source to the Telematics unit withthe satellite network further comprises: configuring an acknowledgmentthat the message received in the first satellite communication has beenreceived in the satellite mode; returning, in a second cellularcommunication communicated, when the cellular network is determined tobe used, from the Telematics unit to the source, the acknowledgment thatthe message has been received in the satellite mode; determining if avehicle is turned off; programmably controlling power to the satellitereceiver when the vehicle is turned off; wherein the act of programmablycontrolling power to the satellite receiver comprises: obtaining on andoff times designated for operating the satellite receiver; andcontrolling supply of power to the satellite receiver based on thedesignated on and off times.
 19. The method of claim 18, the act ofdetermining whether to use the cellular network or the satellite networkto communicate between the Telematics unit and the source of Telematicsservice comprises determining one or more of: whether the cellulartransceiver is capable of communicating with the cellular network,whether the cellular transceiver is out of communication range of thecellular network, whether the cellular network is congested, whether anexpense for using the cellular network exceeds a predetermined amount,and whether using the cellular network is not preferred.
 20. The methodof claim 18, wherein the message comprises one or more instructions, andwherein the method further comprises instructing one or more vehiclecomponents to implement the one or more instructions in the message. 21.The method of claim 18, wherein the act of controlling supply of powerto the satellite receiver based on the designated on and off timescomprises: programming a plurality of timers to track on and off statesin which the satellite receiver is operated, and comparing the timers tothe on and off times designated for operating the satellite receiver.22. The method of claim 18, wherein the act of programmably controllingpower to the satellite receiver comprises; obtaining a total allowableduration designated for powering the satellite receiver; and controllingsupply of power to the satellite receiver based on the total allowableduration.
 23. The method of claim 18, wherein the act of receiving themessage to the first cellular communication communicated from the sourceto the Telematics unit with the cellular network further comprisesreturning an acknowledgment of the message in a second cellularcommunication communicated from the Telematics unit to the source withthe cellular network.
 24. The method of claim 18, further comprising:configuring the acknowledgment that the message has been received in thesatellite mode to indicate that an instruction in the message has beensuccessfully performed.